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Is my canon sensor shot

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#1 andy73

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Posted 19 September 2019 - 12:06 AM

This is the blue channel taken ( as it removes all detail in the image) from an 2 hour stack of Ha stack, ive amplified the exposure to show whats happening these are not moving stars but something else on the sensor .any help please ??

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#2 Jon Rista

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Posted 19 September 2019 - 12:15 AM

Are you calibrating your subs? Looks like hot pixels being dragged across the frame due to drift to me. Walking noise, raining noise. Correlated noise, in that the hot pixels causing this are correlating along a path in the stack, since they are not in the same location in each frame after registration, but are in relatively related (correlated) locations.


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#3 andy73

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Posted 19 September 2019 - 01:08 AM

Hi,
Its usually there if I ad dark frames or not, with darks I do the same amount as lights, I'm guilty as charged for kinda missing out bias frames.
As a dslr sensor temperature changes all the time over night, Do you think darks aid as I thought temperature had to remain constant ? Thank you.

#4 nofxrx

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Posted 20 September 2019 - 10:45 AM

Post the final image with your processing steps or link to the raw stacked image for others to look at, it is easier for us to assess what is wrong that way.

 

Your darks will not be exactly the same temp as your lights unless you took them after each exposure, even then maybe not. Temp isnt regulated so we do as best we can...

However, your camera's (processor's) temp can be found in your EXIF data. If you use BYEOS you can have it put it in the file name and then use that to determine the average temp for the set of subs.

You can then take your darks whenever you want by regulating the ambient temp to achieve nearly the same average temp as your lights...within a few degrees.

 

FWIW I agree with Jon, this looks like typical walking noise. There is nothing on your sensor or wrong with it.

If you dither between exposures it should nearly disappear.

Darks will not remove this. Only dithering will.

(this is all AFAIK or YMMV smile.gif )

Good luck


Edited by nofxrx, 20 September 2019 - 10:45 AM.



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